Gustatory and olfactory sensitivity in patients with anorexia and bulimia in the course of treatment
Introduction
Eating disorders are severe chronic diseases (Fichter et al., 2006). Treatment turns out to be extremely difficult (Halmi et al., 2005). In anorexia nervosa we find the highest mortality rate of all psychiatric disorders with up to 20% (Neumärker, 1997, Patton, 1988, Sullivan, 1995, Vitiello and Lederhendler, 2000). Although the exact etiology of anorexia and bulimia remains unknown until today many studies provide evidence that biological, genetic, sociocultural, psychological as well as personal factors play an important role in the development and maintenance of eating disorders (Bulik et al., 2005, Bulik et al., 2006). Both anorexia and bulimia nervosa mainly occur in adolescent girls and young adult women. Anorexia nervosa has an average prevalence of 0.3% and is characterized by a persistent pursuit of extreme thinness and morbid fear of fatness, accompanied by a distorted body perception (Hoek and van Hoeken, 2003). Patients refuse to eat, loose extreme amounts of weight and show all the somatic consequences of severe malnutrition (Fairburn and Harrison, 2003, Halmi and Falk, 1981, Weiner, 1985). Bulimia nervosa has a prevalence of 1% in young women and is an eating disorder in which the subject engages in recurrent binge eating followed by intentional purging (Hoek and van Hoeken, 2003). The reason for purging is to compensate for the excessive intake of food and typically takes the form of vomiting, inappropriate use of laxatives, excessive exercise or fasting (Fairburn and Harrison, 2003, Johnson et al., 1984, Russell, 1979). Bulimic patients are mostly of normal weight or overweight. Considering disturbed eating patterns in both eating disorders as well as the more as difficult re-feeding/weight gain procedures in patients with anorexia nervosa it is of importance to investigate olfactory and gustatory functions in these patients as efforts to better understand underlying pathophysiology and to improve therapeutic approaches.
Section snippets
Olfactory function and eating disorders
Very few studies have investigated olfactory function in eating disorders. LeGoff et al. (1988) examined the salivary response to olfactory food stimuli in patients with anorexia, bulimia, and healthy controls (n = 6 per group). Before treatment, anorexics salivated less than controls while bulimics salivated more than controls. Following treatment, the salivary response of eating disordered subjects was much closer to controls. In another study (Kopala et al., 1995) the ability to identify odors
Gustatory function and eating disorders
Considering previous work on taste in eating disorders there are studies investigating hedonic, food or taste preferences, studies on gustatory function or sensitivity and there are studies on brain response to taste (results below are reported in the mentioned order).
Drewnowski et al., 1987, Drewnowski et al., 1988 found that eating disordered subjects did not differ from healthy controls (n = 16) as for their sensory estimates of sweetness and fat content of different stimuli. But, both,
Subjects
Subjects in this study were 16 female patients with anorexia nervosa (restricting type), 24 female patients with bulimia nervosa (purging type) and 23 female healthy controls. Anorexic patients were ages 19–32 years (M = 24.5 years, SD = 4.0 years), bulimic patients ages 19–35 years (M = 24.3 years, SD = 4.6 years) and healthy controls ages 18–34 years (M = 24.5 years, SD = 4.8 years). Patients were hospitalized at the inpatient unit of the Department for Psychotherapy and Psychosomatic Medicine of the
Results
Descriptive statistics of the results from the study are summarized in Table 1, separately for the three groups of subjects. Only a portion of the patients could be investigated at discharge, or, was willing to be re-investigated at that time (see Table 1 for details). As for the three anorectic and two bulimic patients treated with an antidepressant we decided to leave these subjects in our sample because comprehensive analyses revealed that the medication did not influence any of the results
Conclusions
The purpose of our longitudinal study was to thoroughly investigate olfactory and gustatory sensitivities in female subjects of three homogeneous narrowly defined diagnostic groups: anorexia (restricting type), bulimia (purging type), and healthy controls. The results show that, in comparison to healthy and bulimic subjects, patients with anorexia nervosa have alterations, specifically, lowered olfactory and gustatory functions that improve in the course of therapy in relation to an increasing
Conflict of Interests
All authors declare that they have no conflict of interests.
Role of Funding Resource
There were no outside funding resources for any of the authors in this study and therefore no involvements of funding resources in the study.
Contributors
Katja Aschenbrenner designed the study, ran subjects and wrote the manuscript and protocol.
Ninette Scholze performed literature searches, ran subjects, helped with the statistical analysis and contributed to parts of the manuscript and the protocol.
Peter Joraschky assisted with the preparation and design of the study and proof reading of the manuscript.
Thomas Hummel undertook the statistical analysis, helped with the preparation of the study and contributed to the results section of the
Acknowledgements
None of the authors wishes to make an acknowledgement.
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